Introduce interface for relay chain interaction (#835)

2026-07-19 23:55:40 +00:00 · 2021-12-22 19:02:11 +01:00
parent 7acfd4f80a
commit 876e594f59
30 changed files with 1512 additions and 1607 deletions
@@ -0,0 +1,542 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Cumulus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::{sync::Arc, time::Duration};
+
+use async_trait::async_trait;
+use cumulus_primitives_core::{
+	relay_chain::{
+		v1::{
+			CommittedCandidateReceipt, OccupiedCoreAssumption, ParachainHost, SessionIndex,
+			ValidatorId,
+		},
+		Block as PBlock, BlockId, Hash as PHash, InboundHrmpMessage,
+	},
+	InboundDownwardMessage, ParaId, PersistedValidationData,
+};
+use cumulus_relay_chain_interface::{RelayChainInterface, WaitError};
+use futures::{FutureExt, StreamExt};
+use parking_lot::Mutex;
+use polkadot_client::{ClientHandle, ExecuteWithClient, FullBackend};
+use polkadot_service::{
+	AuxStore, BabeApi, CollatorPair, Configuration, Handle, NewFull, Role, TaskManager,
+};
+use sc_client_api::{
+	blockchain::BlockStatus, Backend, BlockchainEvents, HeaderBackend, ImportNotifications,
+	StorageProof, UsageProvider,
+};
+use sc_telemetry::TelemetryWorkerHandle;
+use sp_api::{ApiError, ProvideRuntimeApi};
+use sp_consensus::SyncOracle;
+use sp_core::{sp_std::collections::btree_map::BTreeMap, Pair};
+use sp_state_machine::{Backend as StateBackend, StorageValue};
+
+const LOG_TARGET: &str = "relay-chain-local";
+/// The timeout in seconds after that the waiting for a block should be aborted.
+const TIMEOUT_IN_SECONDS: u64 = 6;
+
+/// Provides an implementation of the [`RelayChainInterface`] using a local in-process relay chain node.
+pub struct RelayChainLocal<Client> {
+	full_client: Arc<Client>,
+	backend: Arc<FullBackend>,
+	sync_oracle: Arc<Mutex<Box<dyn SyncOracle + Send + Sync>>>,
+	overseer_handle: Option<Handle>,
+}
+
+impl<Client> RelayChainLocal<Client> {
+	/// Create a new instance of [`RelayChainLocal`]
+	pub fn new(
+		full_client: Arc<Client>,
+		backend: Arc<FullBackend>,
+		sync_oracle: Arc<Mutex<Box<dyn SyncOracle + Send + Sync>>>,
+		overseer_handle: Option<Handle>,
+	) -> Self {
+		Self { full_client, backend, sync_oracle, overseer_handle }
+	}
+}
+
+impl<T> Clone for RelayChainLocal<T> {
+	fn clone(&self) -> Self {
+		Self {
+			full_client: self.full_client.clone(),
+			backend: self.backend.clone(),
+			sync_oracle: self.sync_oracle.clone(),
+			overseer_handle: self.overseer_handle.clone(),
+		}
+	}
+}
+
+#[async_trait]
+impl<Client> RelayChainInterface for RelayChainLocal<Client>
+where
+	Client: ProvideRuntimeApi<PBlock>
+		+ BlockchainEvents<PBlock>
+		+ AuxStore
+		+ UsageProvider<PBlock>
+		+ Sync
+		+ Send,
+	Client::Api: ParachainHost<PBlock> + BabeApi<PBlock>,
+{
+	fn retrieve_dmq_contents(
+		&self,
+		para_id: ParaId,
+		relay_parent: PHash,
+	) -> Option<Vec<InboundDownwardMessage>> {
+		self.full_client
+			.runtime_api()
+			.dmq_contents_with_context(
+				&BlockId::hash(relay_parent),
+				sp_core::ExecutionContext::Importing,
+				para_id,
+			)
+			.map_err(|e| {
+				tracing::error!(
+					target: LOG_TARGET,
+					relay_parent = ?relay_parent,
+					error = ?e,
+					"An error occured during requesting the downward messages.",
+				);
+			})
+			.ok()
+	}
+
+	fn retrieve_all_inbound_hrmp_channel_contents(
+		&self,
+		para_id: ParaId,
+		relay_parent: PHash,
+	) -> Option<BTreeMap<ParaId, Vec<InboundHrmpMessage>>> {
+		self.full_client
+			.runtime_api()
+			.inbound_hrmp_channels_contents_with_context(
+				&BlockId::hash(relay_parent),
+				sp_core::ExecutionContext::Importing,
+				para_id,
+			)
+			.map_err(|e| {
+				tracing::error!(
+					target: LOG_TARGET,
+					relay_parent = ?relay_parent,
+					error = ?e,
+					"An error occured during requesting the inbound HRMP messages.",
+				);
+			})
+			.ok()
+	}
+
+	fn persisted_validation_data(
+		&self,
+		block_id: &BlockId,
+		para_id: ParaId,
+		occupied_core_assumption: OccupiedCoreAssumption,
+	) -> Result<Option<PersistedValidationData>, ApiError> {
+		self.full_client.runtime_api().persisted_validation_data(
+			block_id,
+			para_id,
+			occupied_core_assumption,
+		)
+	}
+
+	fn candidate_pending_availability(
+		&self,
+		block_id: &BlockId,
+		para_id: ParaId,
+	) -> Result<Option<CommittedCandidateReceipt>, ApiError> {
+		self.full_client.runtime_api().candidate_pending_availability(block_id, para_id)
+	}
+
+	fn session_index_for_child(&self, block_id: &BlockId) -> Result<SessionIndex, ApiError> {
+		self.full_client.runtime_api().session_index_for_child(block_id)
+	}
+
+	fn validators(&self, block_id: &BlockId) -> Result<Vec<ValidatorId>, ApiError> {
+		self.full_client.runtime_api().validators(block_id)
+	}
+
+	fn import_notification_stream(&self) -> sc_client_api::ImportNotifications<PBlock> {
+		self.full_client.import_notification_stream()
+	}
+
+	fn finality_notification_stream(&self) -> sc_client_api::FinalityNotifications<PBlock> {
+		self.full_client.finality_notification_stream()
+	}
+
+	fn storage_changes_notification_stream(
+		&self,
+		filter_keys: Option<&[sc_client_api::StorageKey]>,
+		child_filter_keys: Option<
+			&[(sc_client_api::StorageKey, Option<Vec<sc_client_api::StorageKey>>)],
+		>,
+	) -> sc_client_api::blockchain::Result<sc_client_api::StorageEventStream<PHash>> {
+		self.full_client
+			.storage_changes_notification_stream(filter_keys, child_filter_keys)
+	}
+
+	fn best_block_hash(&self) -> PHash {
+		self.backend.blockchain().info().best_hash
+	}
+
+	fn block_status(&self, block_id: BlockId) -> Result<BlockStatus, sp_blockchain::Error> {
+		self.backend.blockchain().status(block_id)
+	}
+
+	fn is_major_syncing(&self) -> bool {
+		let mut network = self.sync_oracle.lock();
+		network.is_major_syncing()
+	}
+
+	fn overseer_handle(&self) -> Option<Handle> {
+		self.overseer_handle.clone()
+	}
+
+	fn get_storage_by_key(
+		&self,
+		block_id: &BlockId,
+		key: &[u8],
+	) -> Result<Option<StorageValue>, sp_blockchain::Error> {
+		let state = self.backend.state_at(*block_id)?;
+		state.storage(key).map_err(sp_blockchain::Error::Storage)
+	}
+
+	fn prove_read(
+		&self,
+		block_id: &BlockId,
+		relevant_keys: &Vec<Vec<u8>>,
+	) -> Result<Option<StorageProof>, Box<dyn sp_state_machine::Error>> {
+		let state_backend = self
+			.backend
+			.state_at(*block_id)
+			.map_err(|e| {
+				tracing::error!(
+					target: LOG_TARGET,
+					relay_parent = ?block_id,
+					error = ?e,
+					"Cannot obtain the state of the relay chain.",
+				);
+			})
+			.ok();
+
+		match state_backend {
+			Some(state) => sp_state_machine::prove_read(state, relevant_keys)
+				.map_err(|e| {
+					tracing::error!(
+						target: LOG_TARGET,
+						relay_parent = ?block_id,
+						error = ?e,
+						"Failed to collect required relay chain state storage proof.",
+					);
+					e
+				})
+				.map(Some),
+			None => Ok(None),
+		}
+	}
+
+	/// Wait for a given relay chain block in an async way.
+	///
+	/// The caller needs to pass the hash of a block it waits for and the function will return when the
+	/// block is available or an error occurred.
+	///
+	/// The waiting for the block is implemented as follows:
+	///
+	/// 1. Get a read lock on the import lock from the backend.
+	///
+	/// 2. Check if the block is already imported. If yes, return from the function.
+	///
+	/// 3. If the block isn't imported yet, add an import notification listener.
+	///
+	/// 4. Poll the import notification listener until the block is imported or the timeout is fired.
+	///
+	/// The timeout is set to 6 seconds. This should be enough time to import the block in the current
+	/// round and if not, the new round of the relay chain already started anyway.
+	async fn wait_for_block(&self, hash: PHash) -> Result<(), WaitError> {
+		let mut listener =
+			match check_block_in_chain(self.backend.clone(), self.full_client.clone(), hash)? {
+				BlockCheckStatus::InChain => return Ok(()),
+				BlockCheckStatus::Unknown(listener) => listener,
+			};
+
+		let mut timeout = futures_timer::Delay::new(Duration::from_secs(TIMEOUT_IN_SECONDS)).fuse();
+
+		loop {
+			futures::select! {
+				_ = timeout => return Err(WaitError::Timeout(hash)),
+				evt = listener.next() => match evt {
+					Some(evt) if evt.hash == hash => return Ok(()),
+					// Not the event we waited on.
+					Some(_) => continue,
+					None => return Err(WaitError::ImportListenerClosed(hash)),
+				}
+			}
+		}
+	}
+}
+
+pub enum BlockCheckStatus {
+	/// Block is in chain
+	InChain,
+	/// Block status is unknown, listener can be used to wait for notification
+	Unknown(ImportNotifications<PBlock>),
+}
+
+// Helper function to check if a block is in chain.
+pub fn check_block_in_chain<Client>(
+	backend: Arc<FullBackend>,
+	client: Arc<Client>,
+	hash: PHash,
+) -> Result<BlockCheckStatus, WaitError>
+where
+	Client: BlockchainEvents<PBlock>,
+{
+	let _lock = backend.get_import_lock().read();
+
+	let block_id = BlockId::Hash(hash);
+	match backend.blockchain().status(block_id) {
+		Ok(BlockStatus::InChain) => return Ok(BlockCheckStatus::InChain),
+		Err(err) => return Err(WaitError::BlockchainError(hash, err)),
+		_ => {},
+	}
+
+	let listener = client.import_notification_stream();
+
+	Ok(BlockCheckStatus::Unknown(listener))
+}
+
+/// Builder for a concrete relay chain interface, created from a full node. Builds
+/// a [`RelayChainLocal`] to access relay chain data necessary for parachain operation.
+///
+/// The builder takes a [`polkadot_client::Client`]
+/// that wraps a concrete instance. By using [`polkadot_client::ExecuteWithClient`]
+/// the builder gets access to this concrete instance and instantiates a [`RelayChainLocal`] with it.
+struct RelayChainLocalBuilder {
+	polkadot_client: polkadot_client::Client,
+	backend: Arc<FullBackend>,
+	sync_oracle: Arc<Mutex<Box<dyn SyncOracle + Send + Sync>>>,
+	overseer_handle: Option<Handle>,
+}
+
+impl RelayChainLocalBuilder {
+	pub fn build(self) -> Arc<dyn RelayChainInterface> {
+		self.polkadot_client.clone().execute_with(self)
+	}
+}
+
+impl ExecuteWithClient for RelayChainLocalBuilder {
+	type Output = Arc<dyn RelayChainInterface>;
+
+	fn execute_with_client<Client, Api, Backend>(self, client: Arc<Client>) -> Self::Output
+	where
+		Client: ProvideRuntimeApi<PBlock>
+			+ BlockchainEvents<PBlock>
+			+ AuxStore
+			+ UsageProvider<PBlock>
+			+ 'static
+			+ Sync
+			+ Send,
+		Client::Api: ParachainHost<PBlock> + BabeApi<PBlock>,
+	{
+		Arc::new(RelayChainLocal::new(client, self.backend, self.sync_oracle, self.overseer_handle))
+	}
+}
+
+/// Build the Polkadot full node using the given `config`.
+#[sc_tracing::logging::prefix_logs_with("Relaychain")]
+fn build_polkadot_full_node(
+	config: Configuration,
+	telemetry_worker_handle: Option<TelemetryWorkerHandle>,
+) -> Result<(NewFull<polkadot_client::Client>, CollatorPair), polkadot_service::Error> {
+	let is_light = matches!(config.role, Role::Light);
+	if is_light {
+		Err(polkadot_service::Error::Sub("Light client not supported.".into()))
+	} else {
+		let collator_key = CollatorPair::generate().0;
+
+		let relay_chain_full_node = polkadot_service::build_full(
+			config,
+			polkadot_service::IsCollator::Yes(collator_key.clone()),
+			None,
+			true,
+			None,
+			telemetry_worker_handle,
+			polkadot_service::RealOverseerGen,
+		)?;
+
+		Ok((relay_chain_full_node, collator_key))
+	}
+}
+
+/// Builds a relay chain interface by constructing a full relay chain node
+pub fn build_relay_chain_interface(
+	polkadot_config: Configuration,
+	telemetry_worker_handle: Option<TelemetryWorkerHandle>,
+	task_manager: &mut TaskManager,
+) -> Result<(Arc<(dyn RelayChainInterface + 'static)>, CollatorPair), polkadot_service::Error> {
+	let (full_node, collator_key) =
+		build_polkadot_full_node(polkadot_config, telemetry_worker_handle).map_err(
+			|e| match e {
+				polkadot_service::Error::Sub(x) => x,
+				s => format!("{}", s).into(),
+			},
+		)?;
+
+	let sync_oracle: Box<dyn SyncOracle + Send + Sync> = Box::new(full_node.network.clone());
+	let sync_oracle = Arc::new(Mutex::new(sync_oracle));
+	let relay_chain_interface_builder = RelayChainLocalBuilder {
+		polkadot_client: full_node.client.clone(),
+		backend: full_node.backend.clone(),
+		sync_oracle,
+		overseer_handle: full_node.overseer_handle.clone(),
+	};
+	task_manager.add_child(full_node.task_manager);
+
+	Ok((relay_chain_interface_builder.build(), collator_key))
+}
+
+#[cfg(test)]
+mod tests {
+	use parking_lot::Mutex;
+
+	use super::*;
+
+	use polkadot_primitives::v1::Block as PBlock;
+	use polkadot_test_client::{
+		construct_transfer_extrinsic, BlockBuilderExt, Client, ClientBlockImportExt,
+		DefaultTestClientBuilderExt, ExecutionStrategy, InitPolkadotBlockBuilder,
+		TestClientBuilder, TestClientBuilderExt,
+	};
+	use sc_service::Arc;
+	use sp_consensus::{BlockOrigin, SyncOracle};
+	use sp_runtime::traits::Block as BlockT;
+
+	use futures::{executor::block_on, poll, task::Poll};
+
+	struct DummyNetwork {}
+
+	impl SyncOracle for DummyNetwork {
+		fn is_major_syncing(&mut self) -> bool {
+			unimplemented!("Not needed for test")
+		}
+
+		fn is_offline(&mut self) -> bool {
+			unimplemented!("Not needed for test")
+		}
+	}
+
+	fn build_client_backend_and_block() -> (Arc<Client>, PBlock, RelayChainLocal<Client>) {
+		let builder =
+			TestClientBuilder::new().set_execution_strategy(ExecutionStrategy::NativeWhenPossible);
+		let backend = builder.backend();
+		let client = Arc::new(builder.build());
+
+		let block_builder = client.init_polkadot_block_builder();
+		let block = block_builder.build().expect("Finalizes the block").block;
+		let dummy_network: Box<dyn SyncOracle + Sync + Send> = Box::new(DummyNetwork {});
+
+		(
+			client.clone(),
+			block,
+			RelayChainLocal::new(
+				client,
+				backend.clone(),
+				Arc::new(Mutex::new(dummy_network)),
+				None,
+			),
+		)
+	}
+
+	#[test]
+	fn returns_directly_for_available_block() {
+		let (mut client, block, relay_chain_interface) = build_client_backend_and_block();
+		let hash = block.hash();
+
+		block_on(client.import(BlockOrigin::Own, block)).expect("Imports the block");
+
+		block_on(async move {
+			// Should be ready on the first poll
+			assert!(matches!(
+				poll!(relay_chain_interface.wait_for_block(hash)),
+				Poll::Ready(Ok(()))
+			));
+		});
+	}
+
+	#[test]
+	fn resolve_after_block_import_notification_was_received() {
+		let (mut client, block, relay_chain_interface) = build_client_backend_and_block();
+		let hash = block.hash();
+
+		block_on(async move {
+			let mut future = relay_chain_interface.wait_for_block(hash);
+			// As the block is not yet imported, the first poll should return `Pending`
+			assert!(poll!(&mut future).is_pending());
+
+			// Import the block that should fire the notification
+			client.import(BlockOrigin::Own, block).await.expect("Imports the block");
+
+			// Now it should have received the notification and report that the block was imported
+			assert!(matches!(poll!(future), Poll::Ready(Ok(()))));
+		});
+	}
+
+	#[test]
+	fn wait_for_block_time_out_when_block_is_not_imported() {
+		let (_, block, relay_chain_interface) = build_client_backend_and_block();
+		let hash = block.hash();
+
+		assert!(matches!(
+			block_on(relay_chain_interface.wait_for_block(hash)),
+			Err(WaitError::Timeout(_))
+		));
+	}
+
+	#[test]
+	fn do_not_resolve_after_different_block_import_notification_was_received() {
+		let (mut client, block, relay_chain_interface) = build_client_backend_and_block();
+		let hash = block.hash();
+
+		let ext = construct_transfer_extrinsic(
+			&*client,
+			sp_keyring::Sr25519Keyring::Alice,
+			sp_keyring::Sr25519Keyring::Bob,
+			1000,
+		);
+		let mut block_builder = client.init_polkadot_block_builder();
+		// Push an extrinsic to get a different block hash.
+		block_builder.push_polkadot_extrinsic(ext).expect("Push extrinsic");
+		let block2 = block_builder.build().expect("Build second block").block;
+		let hash2 = block2.hash();
+
+		block_on(async move {
+			let mut future = relay_chain_interface.wait_for_block(hash);
+			let mut future2 = relay_chain_interface.wait_for_block(hash2);
+			// As the block is not yet imported, the first poll should return `Pending`
+			assert!(poll!(&mut future).is_pending());
+			assert!(poll!(&mut future2).is_pending());
+
+			// Import the block that should fire the notification
+			client.import(BlockOrigin::Own, block2).await.expect("Imports the second block");
+
+			// The import notification of the second block should not make this one finish
+			assert!(poll!(&mut future).is_pending());
+			// Now it should have received the notification and report that the block was imported
+			assert!(matches!(poll!(future2), Poll::Ready(Ok(()))));
+
+			client.import(BlockOrigin::Own, block).await.expect("Imports the first block");
+
+			// Now it should be ready
+			assert!(matches!(poll!(future), Poll::Ready(Ok(()))));
+		});
+	}
+}